English Reference

Word

complexity

Phoneticscom·plex·i·ty

US/kəmˈpɫɛksəti/

UK/kəmplˈɛksɪti/

Definitions

01the state of being complicated

B2

n. the quality of having many different parts that are connected in a difficult way.

n. the abstract state or quality of being intricate, multifaceted, or difficult to analyse. Uncountable in this general sense.

“The complexity of the new tax laws makes them very hard for most people to follow.”

“The sheer complexity of the global supply chain means that a single disruption in one port can affect prices worldwide.”

Academic

Usage

Often used with the preposition 'of' followed by a noun phrase.

Synonyms

02a complicated feature

C1

n. a specific part of something that is difficult to deal with or understand.

n. a specific intricate detail or complication within a larger system. Countable in this sense.

“We need to consider all the complexities of the situation before we make a final decision.”

“The legal team spent months navigating the complexities of the international merger to ensure full compliance with local regulations.”

Academic · Formal

Usage

Frequently used in the plural form 'complexities' to refer to various difficult aspects of a topic.

Real-World Examples

“If we couldn’t make generalisations, we would be paralysed by the world’s complexity.”
Aeon · 10 Aug 2026
“Hysteroscopies are common procedures – classed by the NHS as “high volume low complexity”.”
The Guardian · 16 Aug 2026

Etymology

From complex + -ity. Partially displaced native English manifoldness.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Collocations

add complexityincrease complexityincreased complexityincreasing complexityreduce complexityreflect complexity

Word family

complexAdjectivecomplexityNoun

This entry

Level
C1 · Advanced
Frequency
Common
Updated

Scan code

englishreference.com/q/complexity

English Reference